System and method for managing operational states of a variable displacement compressor based upon climate conditions

Abstract

A system is disclosed. The system includes a climate condition determination module that is configured to determine a climate condition associated with a vehicle based upon an external air temperature or a dew point temperature. The system also includes a compressor operational state control module that is configured to control a plurality of operational states of a variable displacement compressor of a heating, ventilation and air conditioning system within the vehicle. The compressor operational state control module is configured to cause the variable displacement compressor to selectively transition from a variable displacement operational state to a fixed displacement-like operational state when the climate condition exceeds a climate threshold to cause an evaporator of the heating, ventilation and air conditioning system to provide evaporator air having an air temperature corresponding to a target evaporator air temperature.

What is claimed is: 
     
       1. A system comprising:
 a climate condition determination module that is configured to determine a climate condition associated with a vehicle based upon at least one of an external air temperature and a dew point temperature; and 
 a compressor operational state control module that is configured to control a plurality of operational states of a variable displacement compressor of a heating, ventilation and air conditioning system within the vehicle, the compressor operational state control module configured to:
 cause the variable displacement compressor to selectively transition from a variable displacement operational state to a fixed displacement-like operational state when the climate condition exceeds a climate threshold, wherein an evaporator of the heating, ventilation and air conditioning system provides evaporator air having an air temperature corresponding to a target evaporator air temperature when the variable displacement compressor is in the fixed displacement-like operational state, 
 wherein the climate condition is based upon the external air temperature and the dew point temperature, 
 wherein the climate condition exceeds the climate threshold when the external air temperature is greater than or equal to an external temperature threshold and the dew point temperature does not exceed a dew point threshold. 
 
 
     
     
       2. The system as recited in  claim 1  further comprising a timer module that is configured to increment a time counter when the climate condition exceeds a climate threshold, wherein the compressor operational state control module is further configured to selectively transition between a minimum and a maximum evaporator air target temperatures to produce a fixed displacement-like operation with the variable displacement compressor. 
     
     
       3. The system as recited in  claim 2  wherein the compressor operational state control module is further configured to maintain a cyclic mode of operation flag based upon the climate condition. 
     
     
       4. The system as recited in  claim 3  wherein the cyclic mode of operation flag is set to Boolean true when the climate condition exceeds the climate threshold and is set to Boolean false when the climate condition does not exceed the climate threshold. 
     
     
       5. The system as recited in  claim 4  wherein the compressor operational state control module is further configured to cause the variable displacement compressor to operate in the fixed displacement-like operational state when the cyclic mode of operation flag is set to Boolean true and the time counter does not exceed a predefined time period. 
     
     
       6. The system as recited in  claim 4  wherein the compressor operational state control module is further configured to cause the variable displacement compressor to transition from the fixed displacement-like operational state to the variable displacement operational state when the cyclic mode of operation flag is set to Boolean true and the time counter exceeds a predefined time period. 
     
     
       7. The system as recited in  claim 1  further comprising a dew point determination module that is configured to determine the dew point temperature based upon at least one of a cabin air humidity characteristic, an external air humidity characteristic, and an air inlet mixing radio. 
     
     
       8. The system as recited in  claim 1  further comprising an external temperature determination module that is configured to determine the external air temperature. 
     
     
       9. A method comprising:
 determining a climate condition pertaining to a vehicle based upon at least one of an external air temperature and a dew point temperature; and 
 causing a variable displacement compressor of a heating, ventilation and air conditioning system within the vehicle to selectively transition from a variable displacement operational state to a fixed displacement-like operational state when the climate condition exceeds a climate threshold, wherein an evaporator of the heating, ventilation and air conditioning system provides evaporator air having an air temperature corresponding to a target evaporator air temperature when the variable displacement compressor is in the fixed displacement-like operational state, 
 wherein the climate condition is based upon the external air temperature and the dew point temperature, 
 wherein the climate condition exceeds the climate threshold when the external air temperature is greater than or equal to an external temperature threshold and the dew point temperature does not exceed a dew point threshold. 
 
     
     
       10. The method as recited in  claim 9  further comprising incrementing a time counter when the climate condition exceeds a climate threshold; and causing the variable displacement compressor to selectively transition from the fixed displacement-like operational state to the variable displacement operational state when the time counter exceeds a predefined time period. 
     
     
       11. The method as recited in  claim 10  further comprising maintaining a cyclic mode of operation flag based upon the climate condition. 
     
     
       12. The method as recited in  claim 11  wherein the cyclic mode of operation flag is set to Boolean true when the climate condition exceeds the climate threshold and is set to Boolean false when the climate condition does not exceed the climate threshold. 
     
     
       13. The method as recited in  claim 12  further comprising causing the variable displacement compressor to operate in the fixed displacement-like operational state when the cyclic mode of operation flag is set to Boolean true and the time counter does not exceed the predefined time period. 
     
     
       14. The method as recited in  claim 12  further comprising causing the variable displacement compressor to transition from the fixed displacement-like operational state to the variable displacement operational state when the cyclic mode of operation flag is set to Boolean true and the time counter exceeds the predefined time period. 
     
     
       15. The method as recited in  claim 9  further comprising determining the dew point temperature based upon at least one of a cabin air humidity characteristic, an external air humidity characteristic, and an air inlet mixing radio. 
     
     
       16. The method as recited in  claim 9  further comprising determining the external air temperature.